Changing default border thickness to be 0 instead of 1.

Author: Keboo

MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.Button.xaml

@@ -96,7 +96,7 @@
         <Setter Property="wpf:RippleAssist.Feedback" Value="{DynamicResource MaterialDesignFlatButtonRipple}" />
         <Setter Property="TextBlock.FontWeight" Value="Medium"/>
         <Setter Property="TextBlock.FontSize" Value="14"/>
-        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="BorderThickness" Value="0"/>
         <Setter Property="HorizontalContentAlignment" Value="Center"/>
         <Setter Property="VerticalContentAlignment" Value="Center"/>
         <Setter Property="Padding" Value="16 4 16 4"/>